diff options
| -rw-r--r-- | guix/utils.scm | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/guix/utils.scm b/guix/utils.scm index 7306c6011d..84cb5ae983 100644 --- a/guix/utils.scm +++ b/guix/utils.scm @@ -377,14 +377,30 @@ closed as soon as PROC's dynamic extent is entered." (let ((proc (pointer->procedure '* errno-loc '()))) (proc))))) -(define (errno) - "Return the current errno." - ;; XXX: We assume that nothing changes 'errno' while we're doing all this. - ;; In particular, that means that no async must be running here. +(define errno (if %libc-errno-pointer (let ((bv (pointer->bytevector %libc-errno-pointer (sizeof int)))) - (bytevector-sint-ref bv 0 (native-endianness) (sizeof int))) - 0)) + (lambda () + "Return the current errno." + ;; XXX: We assume that nothing changes 'errno' while we're doing all this. + ;; In particular, that means that no async must be running here. + + ;; Use one of the fixed-size native-ref procedures because they are + ;; optimized down to a single VM instruction, which reduces the risk + ;; that we fiddle with 'errno' (needed on Guile 2.0.5, libc 2.11.) + (let-syntax ((ref (lambda (s) + (syntax-case s () + ((_ bv) + (case (sizeof int) + ((4) + #'(bytevector-s32-native-ref bv 0)) + ((8) + #'(bytevector-s64-native-ref bv 0)) + (else + (error "unsupported 'int' size" + (sizeof int))))))))) + (ref bv)))) + (lambda () 0))) (define fcntl-flock (let* ((ptr (dynamic-func "fcntl" (dynamic-link))) |