After some more research and overthinking things, I found the culprit: Using LAPACK_ROW_MAJOR switches the meaning of the ld* leading dimension parameters. While the leading dimension of a normal Fortran array is the numbers of rows, switching to ROW_MAJOR switches its meaning to the number of columns. So the correct...

c,linear-algebra,lapack,lapacke

When it comes to documentation for BLAS and/or LAPACK, Intel is probably the most comprehensive out there. You can look up the docs for ?ptsv, which explains what each parameter is for. (Hint: when searching for a BLAS or LAPACK in Google, be sure to drop the s/d/c/z prefix.) Here's...