From a0af678f60708a5718614403889bd0285105d2a6 Mon Sep 17 00:00:00 2001
From: Chaitanya-970 <chaitanyabh97@gmail.com>
Date: Thu, 15 Oct 2026 23:24:08 +0530
Subject: [PATCH 1/3] Fix declaration order in external BLAS/LAPACK interfaces

---
 .github/workflows/ci_BLAS.yml        | 26 +++++---
 CHANGELOG.md                         |  3 +
 src/blas/stdlib_linalg_blas.fypp     | 88 ++++++++++++++--------------
 src/lapack/stdlib_linalg_lapack.fypp | 42 +++++++------
 4 files changed, 85 insertions(+), 74 deletions(-)

diff --git a/.github/workflows/ci_BLAS.yml b/.github/workflows/ci_BLAS.yml
index 7195c1d61..20b4a128e 100644
--- a/.github/workflows/ci_BLAS.yml
+++ b/.github/workflows/ci_BLAS.yml
@@ -75,7 +75,8 @@ jobs:
       fail-fast: false
       matrix:
         toolchain:
-          - { compiler: intel, version: "2024.1" }
+          - { compiler: intel, version: "2024.1", build_type: Release }
+          - { compiler: gcc, version: 14, build_type: Debug }
         build: [cmake]
     env:
       BUILD_DIR: ${{ matrix.build == 'cmake' && 'build' || '.' }}
@@ -102,29 +103,38 @@ jobs:
           version: ${{ matrix.toolchain.version }}
 
       - name: Install Intel oneAPI MKL
+        if: ${{ matrix.toolchain.compiler == 'intel' }}
         run: |
           sudo apt-get install ${APT_PACKAGES}
           source /opt/intel/oneapi/mkl/latest/env/vars.sh
           printenv >> $GITHUB_ENV
 
-      # Build and test with external BLAS and LAPACK (MKL on Ubuntu with Intel compilers)
-      - name: Configure with CMake and MKL
+      - name: Install OpenBLAS and LAPACK
+        if: ${{ matrix.toolchain.compiler == 'gcc' }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libopenblas-dev liblapack-dev
+
+      # Build and test with external BLAS and LAPACK
+      - name: Configure with CMake
         run: >-
           cmake -Wdev -G Ninja
-          -DCMAKE_BUILD_TYPE=Release
+          -DCMAKE_BUILD_TYPE=${{ matrix.toolchain.build_type }}
           -DCMAKE_MAXIMUM_RANK:String=4
           -DCMAKE_INSTALL_PREFIX=$PWD/_dist
           -DFIND_BLAS:STRING=TRUE
+          -DCMAKE_REQUIRE_FIND_PACKAGE_BLAS=ON
+          -DCMAKE_REQUIRE_FIND_PACKAGE_LAPACK=ON
           -S . -B ${{ env.BUILD_DIR }}
 
-      - name: Build and compile with MKL
+      - name: Build and compile
         run: cmake --build ${{ env.BUILD_DIR }} --parallel
 
-      - name: catch build fail with MKL
+      - name: catch build fail
         if: failure()
         run: cmake --build ${{ env.BUILD_DIR }} --verbose --parallel 1
 
-      - name: test with MKL
+      - name: test
         run: >-
           ctest
           --test-dir ${{ env.BUILD_DIR }}
@@ -132,5 +142,5 @@ jobs:
           --output-on-failure
           --no-tests=error
 
-      - name: Install project with MKL
+      - name: Install project
         run: cmake --install ${{ env.BUILD_DIR }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8deb7c9db..eea778ce6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,9 @@
 ## Unreleased
 
 Changes to the existing modules
+  - Fixed declaration order in external BLAS/LAPACK interfaces for compilation
+    with gfortran under `-std=f2018`
+    [#1210](https://github.com/fortran-lang/stdlib/issues/1210)
   - Change in module `stdlib_system`
     - Added `set_environment_variable` and `delete_environment_variable`
       [#1187](https://github.com/fortran-lang/stdlib/issues/1187)
diff --git a/src/blas/stdlib_linalg_blas.fypp b/src/blas/stdlib_linalg_blas.fypp
index 61f047bd4..d9eddd39a 100644
--- a/src/blas/stdlib_linalg_blas.fypp
+++ b/src/blas/stdlib_linalg_blas.fypp
@@ -285,8 +285,8 @@ module stdlib_linalg_blas
                pure subroutine cgbmv(trans,m,n,kl,ku,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,kl,ku,lda,m,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     complex(sp), intent(inout) :: y(*)
                end subroutine cgbmv
@@ -297,8 +297,8 @@ module stdlib_linalg_blas
                pure subroutine dgbmv(trans,m,n,kl,ku,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,kl,ku,lda,m,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     real(dp), intent(inout) :: y(*)
                end subroutine dgbmv
@@ -309,8 +309,8 @@ module stdlib_linalg_blas
                pure subroutine sgbmv(trans,m,n,kl,ku,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,kl,ku,lda,m,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     real(sp), intent(inout) :: y(*)
                end subroutine sgbmv
@@ -321,8 +321,8 @@ module stdlib_linalg_blas
                pure subroutine zgbmv(trans,m,n,kl,ku,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,kl,ku,lda,m,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     complex(dp), intent(inout) :: y(*)
                end subroutine zgbmv
@@ -349,8 +349,8 @@ module stdlib_linalg_blas
                pure subroutine cgemm(transa,transb,m,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,m,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: transa,transb
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine cgemm
@@ -361,8 +361,8 @@ module stdlib_linalg_blas
                pure subroutine dgemm(transa,transb,m,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,m,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: transa,transb
                     real(dp), intent(inout) :: c(ldc,*)
                end subroutine dgemm
@@ -373,8 +373,8 @@ module stdlib_linalg_blas
                pure subroutine sgemm(transa,transb,m,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,m,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: transa,transb
                     real(sp), intent(inout) :: c(ldc,*)
                end subroutine sgemm
@@ -385,8 +385,8 @@ module stdlib_linalg_blas
                pure subroutine zgemm(transa,transb,m,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,m,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: transa,transb
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zgemm
@@ -412,8 +412,8 @@ module stdlib_linalg_blas
                pure subroutine cgemv(trans,m,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     complex(sp), intent(inout) :: y(*)
                end subroutine cgemv
@@ -424,8 +424,8 @@ module stdlib_linalg_blas
                pure subroutine dgemv(trans,m,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     real(dp), intent(inout) :: y(*)
                end subroutine dgemv
@@ -436,8 +436,8 @@ module stdlib_linalg_blas
                pure subroutine sgemv(trans,m,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     real(sp), intent(inout) :: y(*)
                end subroutine sgemv
@@ -448,8 +448,8 @@ module stdlib_linalg_blas
                pure subroutine zgemv(trans,m,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: trans
                     complex(dp), intent(inout) :: y(*)
                end subroutine zgemv
@@ -584,8 +584,8 @@ module stdlib_linalg_blas
                pure subroutine chbmv(uplo,n,k,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,k,lda,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     complex(sp), intent(inout) :: y(*)
                end subroutine chbmv
@@ -596,8 +596,8 @@ module stdlib_linalg_blas
                pure subroutine zhbmv(uplo,n,k,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,k,lda,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     complex(dp), intent(inout) :: y(*)
                end subroutine zhbmv
@@ -625,8 +625,8 @@ module stdlib_linalg_blas
                pure subroutine chemm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine chemm
@@ -637,8 +637,8 @@ module stdlib_linalg_blas
                pure subroutine zhemm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zhemm
@@ -664,8 +664,8 @@ module stdlib_linalg_blas
                pure subroutine chemv(uplo,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     complex(sp), intent(inout) :: y(*)
                end subroutine chemv
@@ -676,8 +676,8 @@ module stdlib_linalg_blas
                pure subroutine zhemv(uplo,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     complex(dp), intent(inout) :: y(*)
                end subroutine zhemv
@@ -786,9 +786,9 @@ module stdlib_linalg_blas
                pure subroutine cher2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
+                    integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
                     complex(sp), intent(in) :: alpha,a(lda,*),b(ldb,*)
                     real(sp), intent(in) :: beta
-                    integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
                     character, intent(in) :: trans,uplo
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine cher2k
@@ -799,9 +799,9 @@ module stdlib_linalg_blas
                pure subroutine zher2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
+                    integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
                     complex(dp), intent(in) :: alpha,a(lda,*),b(ldb,*)
                     real(dp), intent(in) :: beta
-                    integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
                     character, intent(in) :: trans,uplo
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zher2k
@@ -1247,8 +1247,8 @@ module stdlib_linalg_blas
                pure subroutine dsbmv(uplo,n,k,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,k,lda,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     real(dp), intent(inout) :: y(*)
                end subroutine dsbmv
@@ -1259,8 +1259,8 @@ module stdlib_linalg_blas
                pure subroutine ssbmv(uplo,n,k,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,k,lda,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     real(sp), intent(inout) :: y(*)
                end subroutine ssbmv
@@ -1573,8 +1573,8 @@ module stdlib_linalg_blas
                pure subroutine csymm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine csymm
@@ -1585,8 +1585,8 @@ module stdlib_linalg_blas
                pure subroutine dsymm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     real(dp), intent(inout) :: c(ldc,*)
                end subroutine dsymm
@@ -1597,8 +1597,8 @@ module stdlib_linalg_blas
                pure subroutine ssymm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     real(sp), intent(inout) :: c(ldc,*)
                end subroutine ssymm
@@ -1609,8 +1609,8 @@ module stdlib_linalg_blas
                pure subroutine zsymm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: lda,ldb,ldc,m,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: side,uplo
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zsymm
@@ -1635,8 +1635,8 @@ module stdlib_linalg_blas
                pure subroutine dsymv(uplo,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     real(dp), intent(inout) :: y(*)
                end subroutine dsymv
@@ -1647,8 +1647,8 @@ module stdlib_linalg_blas
                pure subroutine ssymv(uplo,n,alpha,a,lda,x,incx,beta,y,incy)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     character, intent(in) :: uplo
                     real(sp), intent(inout) :: y(*)
                end subroutine ssymv
@@ -1752,8 +1752,8 @@ module stdlib_linalg_blas
                pure subroutine csyr2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: trans,uplo
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine csyr2k
@@ -1764,8 +1764,8 @@ module stdlib_linalg_blas
                pure subroutine dsyr2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: trans,uplo
                     real(dp), intent(inout) :: c(ldc,*)
                end subroutine dsyr2k
@@ -1776,8 +1776,8 @@ module stdlib_linalg_blas
                pure subroutine ssyr2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: trans,uplo
                     real(sp), intent(inout) :: c(ldc,*)
                end subroutine ssyr2k
@@ -1788,8 +1788,8 @@ module stdlib_linalg_blas
                pure subroutine zsyr2k(uplo,trans,n,k,alpha,a,lda,b,ldb,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     integer(${ik}$), intent(in) :: k,lda,ldb,ldc,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*),b(ldb,*)
                     character, intent(in) :: trans,uplo
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zsyr2k
@@ -1817,8 +1817,8 @@ module stdlib_linalg_blas
                pure subroutine csyrk(uplo,trans,n,k,alpha,a,lda,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,ldc,n
+                    complex(sp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,uplo
                     complex(sp), intent(inout) :: c(ldc,*)
                end subroutine csyrk
@@ -1829,8 +1829,8 @@ module stdlib_linalg_blas
                pure subroutine dsyrk(uplo,trans,n,k,alpha,a,lda,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,ldc,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,uplo
                     real(dp), intent(inout) :: c(ldc,*)
                end subroutine dsyrk
@@ -1841,8 +1841,8 @@ module stdlib_linalg_blas
                pure subroutine ssyrk(uplo,trans,n,k,alpha,a,lda,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,ldc,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,uplo
                     real(sp), intent(inout) :: c(ldc,*)
                end subroutine ssyrk
@@ -1853,8 +1853,8 @@ module stdlib_linalg_blas
                pure subroutine zsyrk(uplo,trans,n,k,alpha,a,lda,beta,c,ldc)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,ldc,n
+                    complex(dp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,uplo
                     complex(dp), intent(inout) :: c(ldc,*)
                end subroutine zsyrk
@@ -2133,8 +2133,8 @@ module stdlib_linalg_blas
                pure subroutine ctrmm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    complex(sp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     complex(sp), intent(inout) :: b(ldb,*)
                end subroutine ctrmm
@@ -2145,8 +2145,8 @@ module stdlib_linalg_blas
                pure subroutine dtrmm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    real(dp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     real(dp), intent(inout) :: b(ldb,*)
                end subroutine dtrmm
@@ -2157,8 +2157,8 @@ module stdlib_linalg_blas
                pure subroutine strmm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    real(sp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     real(sp), intent(inout) :: b(ldb,*)
                end subroutine strmm
@@ -2169,8 +2169,8 @@ module stdlib_linalg_blas
                pure subroutine ztrmm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    complex(dp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     complex(dp), intent(inout) :: b(ldb,*)
                end subroutine ztrmm
@@ -2259,8 +2259,8 @@ module stdlib_linalg_blas
                pure subroutine ctrsm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    complex(sp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     complex(sp), intent(inout) :: b(ldb,*)
                end subroutine ctrsm
@@ -2271,8 +2271,8 @@ module stdlib_linalg_blas
                pure subroutine dtrsm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    real(dp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     real(dp), intent(inout) :: b(ldb,*)
                end subroutine dtrsm
@@ -2283,8 +2283,8 @@ module stdlib_linalg_blas
                pure subroutine strsm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    real(sp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     real(sp), intent(inout) :: b(ldb,*)
                end subroutine strsm
@@ -2295,8 +2295,8 @@ module stdlib_linalg_blas
                pure subroutine ztrsm(side,uplo,transa,diag,m,n,alpha,a,lda,b,ldb)
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: alpha,a(lda,*)
                     integer(${ik}$), intent(in) :: lda,ldb,m,n
+                    complex(dp), intent(in) :: alpha,a(lda,*)
                     character, intent(in) :: diag,side,transa,uplo
                     complex(dp), intent(inout) :: b(ldb,*)
                end subroutine ztrsm
diff --git a/src/lapack/stdlib_linalg_lapack.fypp b/src/lapack/stdlib_linalg_lapack.fypp
index 9ec8c95e9..01b899075 100644
--- a/src/lapack/stdlib_linalg_lapack.fypp
+++ b/src/lapack/stdlib_linalg_lapack.fypp
@@ -8352,8 +8352,8 @@ module stdlib_linalg_lapack
 
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,ab(ldab,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,ldab,m,n,kl,ku,trans
+                    real(dp), intent(in) :: alpha,beta,ab(ldab,*),x(*)
                     real(dp), intent(inout) :: y(*)
                end subroutine dla_gbamv
 #else
@@ -8364,8 +8364,8 @@ module stdlib_linalg_lapack
 
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,ab(ldab,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,ldab,m,n,kl,ku,trans
+                    real(sp), intent(in) :: alpha,beta,ab(ldab,*),x(*)
                     real(sp), intent(inout) :: y(*)
                end subroutine sla_gbamv
 #else
@@ -8592,8 +8592,8 @@ module stdlib_linalg_lapack
                subroutine dla_geamv ( trans, m, n, alpha, a, lda, x, incx, beta,y, incy )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n,trans
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     real(dp), intent(inout) :: y(*)
                end subroutine dla_geamv
 #else
@@ -8603,8 +8603,8 @@ module stdlib_linalg_lapack
                subroutine sla_geamv( trans, m, n, alpha, a, lda, x, incx, beta,y, incy )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,m,n,trans
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     real(sp), intent(inout) :: y(*)
                end subroutine sla_geamv
 #else
@@ -9196,8 +9196,8 @@ module stdlib_linalg_lapack
                subroutine dla_syamv( uplo, n, alpha, a, lda, x, incx, beta, y,incy )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n,uplo
+                    real(dp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     real(dp), intent(inout) :: y(*)
                end subroutine dla_syamv
 #else
@@ -9207,8 +9207,8 @@ module stdlib_linalg_lapack
                subroutine sla_syamv( uplo, n, alpha, a, lda, x, incx, beta, y,incy )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     integer(${ik}$), intent(in) :: incx,incy,lda,n,uplo
+                    real(sp), intent(in) :: alpha,beta,a(lda,*),x(*)
                     real(sp), intent(inout) :: y(*)
                end subroutine sla_syamv
 #else
@@ -13630,8 +13630,8 @@ module stdlib_linalg_lapack
                pure subroutine claqr1( n, h, ldh, s1, s2, v )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(sp), intent(in) :: s1,s2,h(ldh,*)
                     integer(${ik}$), intent(in) :: ldh,n
+                    complex(sp), intent(in) :: s1,s2,h(ldh,*)
                     complex(sp), intent(out) :: v(*)
                end subroutine claqr1
 #else
@@ -13641,8 +13641,8 @@ module stdlib_linalg_lapack
                pure subroutine dlaqr1( n, h, ldh, sr1, si1, sr2, si2, v )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: si1,si2,sr1,sr2,h(ldh,*)
                     integer(${ik}$), intent(in) :: ldh,n
+                    real(dp), intent(in) :: si1,si2,sr1,sr2,h(ldh,*)
                     real(dp), intent(out) :: v(*)
                end subroutine dlaqr1
 #else
@@ -13652,8 +13652,8 @@ module stdlib_linalg_lapack
                pure subroutine slaqr1( n, h, ldh, sr1, si1, sr2, si2, v )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: si1,si2,sr1,sr2,h(ldh,*)
                     integer(${ik}$), intent(in) :: ldh,n
+                    real(sp), intent(in) :: si1,si2,sr1,sr2,h(ldh,*)
                     real(sp), intent(out) :: v(*)
                end subroutine slaqr1
 #else
@@ -13663,8 +13663,8 @@ module stdlib_linalg_lapack
                pure subroutine zlaqr1( n, h, ldh, s1, s2, v )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    complex(dp), intent(in) :: s1,s2,h(ldh,*)
                     integer(${ik}$), intent(in) :: ldh,n
+                    complex(dp), intent(in) :: s1,s2,h(ldh,*)
                     complex(dp), intent(out) :: v(*)
                end subroutine zlaqr1
 #else
@@ -16484,9 +16484,8 @@ module stdlib_linalg_lapack
                          info )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),iwork(*),perm(*)
-
                     integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
+                    integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),iwork(*),perm(*)
                     real(dp), intent(inout) :: alpha,beta,d(*),vf(*),vl(*)
                     real(dp), intent(out) :: c,s,difl(*),difr(*),givnum(ldgnum,*),poles(ldgnum,*),&
                               work(*),z(*)
@@ -16501,9 +16500,8 @@ module stdlib_linalg_lapack
                          info )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),iwork(*),perm(*)
-
                     integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
+                    integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),iwork(*),perm(*)
                     real(sp), intent(inout) :: alpha,beta,d(*),vf(*),vl(*)
                     real(sp), intent(out) :: c,s,difl(*),difr(*),givnum(ldgnum,*),poles(ldgnum,*),&
                               work(*),z(*)
@@ -16536,9 +16534,9 @@ module stdlib_linalg_lapack
                          info )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
+                    integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
                     integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),idx(*),idxp(*),&
                               perm(*)
-                    integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
                     real(dp), intent(in) :: alpha,beta
                     real(dp), intent(out) :: c,s,dsigma(*),givnum(ldgnum,*),vfw(*),vlw(*),z(*),zw(&
                               *)
@@ -16554,9 +16552,9 @@ module stdlib_linalg_lapack
                          info )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
+                    integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
                     integer(${ik}$), intent(out) :: givptr,info,k,givcol(ldgcol,*),idx(*),idxp(*),&
                               perm(*)
-                    integer(${ik}$), intent(in) :: icompq,ldgcol,ldgnum,nl,nr,sqre
                     real(sp), intent(in) :: alpha,beta
                     real(sp), intent(out) :: c,s,dsigma(*),givnum(ldgnum,*),vfw(*),vlw(*),z(*),zw(&
                               *)
@@ -22011,8 +22009,8 @@ module stdlib_linalg_lapack
                     import sp,dp,qp,${ik}$,lk
                     implicit none
                     real(sp), intent(in) :: tol
-                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     integer(${ik}$), intent(in) :: lda,n
+                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     character, intent(in) :: uplo
                     complex(sp), intent(inout) :: a(lda,*)
                     real(sp), intent(out) :: work(2*n)
@@ -22025,8 +22023,8 @@ module stdlib_linalg_lapack
                     import sp,dp,qp,${ik}$,lk
                     implicit none
                     real(dp), intent(in) :: tol
-                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     integer(${ik}$), intent(in) :: lda,n
+                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     character, intent(in) :: uplo
                     real(dp), intent(inout) :: a(lda,*)
                     real(dp), intent(out) :: work(2*n)
@@ -22039,8 +22037,8 @@ module stdlib_linalg_lapack
                     import sp,dp,qp,${ik}$,lk
                     implicit none
                     real(sp), intent(in) :: tol
-                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     integer(${ik}$), intent(in) :: lda,n
+                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     character, intent(in) :: uplo
                     real(sp), intent(inout) :: a(lda,*)
                     real(sp), intent(out) :: work(2*n)
@@ -22053,8 +22051,8 @@ module stdlib_linalg_lapack
                     import sp,dp,qp,${ik}$,lk
                     implicit none
                     real(dp), intent(in) :: tol
-                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     integer(${ik}$), intent(in) :: lda,n
+                    integer(${ik}$), intent(out) :: info,rank,piv(n)
                     character, intent(in) :: uplo
                     complex(dp), intent(inout) :: a(lda,*)
                     real(dp), intent(out) :: work(2*n)
@@ -22927,8 +22925,8 @@ module stdlib_linalg_lapack
                pure subroutine dsfrk( transr, uplo, trans, n, k, alpha, a, lda, beta,c )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(dp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,n
+                    real(dp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,transr,uplo
                     real(dp), intent(inout) :: c(*)
                end subroutine dsfrk
@@ -22939,8 +22937,8 @@ module stdlib_linalg_lapack
                pure subroutine ssfrk( transr, uplo, trans, n, k, alpha, a, lda, beta,c )
                     import sp,dp,qp,${ik}$,lk
                     implicit none
-                    real(sp), intent(in) :: alpha,beta,a(lda,*)
                     integer(${ik}$), intent(in) :: k,lda,n
+                    real(sp), intent(in) :: alpha,beta,a(lda,*)
                     character, intent(in) :: trans,transr,uplo
                     real(sp), intent(inout) :: c(*)
                end subroutine ssfrk

From 648a671f598b8ea4fa1701b3f38ea230cc7f1936 Mon Sep 17 00:00:00 2001
From: Chaitanya-970 <chaitanyabh97@gmail.com>
Date: Fri, 16 Oct 2026 00:12:28 +0530
Subject: [PATCH 2/3] Check external interface conformance separately from the
 full build

---
 .github/workflows/ci_BLAS.yml | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci_BLAS.yml b/.github/workflows/ci_BLAS.yml
index 20b4a128e..981c43617 100644
--- a/.github/workflows/ci_BLAS.yml
+++ b/.github/workflows/ci_BLAS.yml
@@ -75,8 +75,8 @@ jobs:
       fail-fast: false
       matrix:
         toolchain:
-          - { compiler: intel, version: "2024.1", build_type: Release }
-          - { compiler: gcc, version: 14, build_type: Debug }
+          - { compiler: intel, version: "2024.1" }
+          - { compiler: gcc, version: 14 }
         build: [cmake]
     env:
       BUILD_DIR: ${{ matrix.build == 'cmake' && 'build' || '.' }}
@@ -119,7 +119,7 @@ jobs:
       - name: Configure with CMake
         run: >-
           cmake -Wdev -G Ninja
-          -DCMAKE_BUILD_TYPE=${{ matrix.toolchain.build_type }}
+          -DCMAKE_BUILD_TYPE=Release
           -DCMAKE_MAXIMUM_RANK:String=4
           -DCMAKE_INSTALL_PREFIX=$PWD/_dist
           -DFIND_BLAS:STRING=TRUE
@@ -130,6 +130,22 @@ jobs:
       - name: Build and compile
         run: cmake --build ${{ env.BUILD_DIR }} --parallel
 
+      - name: Check external interfaces with Fortran 2018
+        if: ${{ matrix.toolchain.compiler == 'gcc' }}
+        run: |
+          # Keep the strict check focused on the external interfaces until #1209 is resolved.
+          module_flags=()
+          while IFS= read -r module_dir; do
+            module_flags+=("-I${module_dir}")
+          done < <(find "${{ env.BUILD_DIR }}/src" -type d -path '*/mod_files/*')
+          strict_dir="${{ env.BUILD_DIR }}/strict-interfaces"
+          mkdir -p "$strict_dir"
+          "$FC" -std=f2018 -fimplicit-none -fsyntax-only \
+            -DSTDLIB_EXTERNAL_BLAS -DSTDLIB_EXTERNAL_LAPACK \
+            -J "$strict_dir" "${module_flags[@]}" \
+            "${{ env.BUILD_DIR }}/src/blas/stdlib_linalg_blas.F90" \
+            "${{ env.BUILD_DIR }}/src/lapack/stdlib_linalg_lapack.F90"
+
       - name: catch build fail
         if: failure()
         run: cmake --build ${{ env.BUILD_DIR }} --verbose --parallel 1

From e011ebf8ae2d4b31e2883aa47ce1916326c01c95 Mon Sep 17 00:00:00 2001
From: Chaitanya-970 <chaitanyabh97@gmail.com>
Date: Fri, 16 Oct 2026 00:23:39 +0530
Subject: [PATCH 3/3] Fix plain library names in pkg-config linker flags

---
 CHANGELOG.md           | 1 +
 config/export_pc.cmake | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index eea778ce6..05a9bc2e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ Changes to the existing modules
       [#1187](https://github.com/fortran-lang/stdlib/issues/1187)
 
 Changes to the existing build system
+  - Fixed missing `-l` prefixes for system libraries in generated pkg-config files
   - Fixed absolute paths in generated pkg-config file for external BLAS/LAPACK 
     [#1109](https://github.com/fortran-lang/stdlib/issues/1109)
 
diff --git a/config/export_pc.cmake b/config/export_pc.cmake
index 321c1ee96..4929e2589 100644
--- a/config/export_pc.cmake
+++ b/config/export_pc.cmake
@@ -47,8 +47,10 @@ function(resolve_pc_libs out_var root_target)
                 string(REGEX REPLACE "\\.framework$" "" _fw_name "${_fw_name}")
                 get_filename_component(_fw_dir "${target}" DIRECTORY)
                 list(APPEND _result "-F${_fw_dir} -framework ${_fw_name}")
-            else()
+            elseif(IS_ABSOLUTE "${target}" OR "${target}" MATCHES "^-")
                 list(APPEND _result "${target}")
+            else()
+                list(APPEND _result "-l${target}")
             endif()
         endif()