Hi, The Linux man page for ptsname_r, when describing the behaviour in the error case, is - not consistent with the future POSIX standard (POSIX Issue 8). - not consistent with musl libc. Find attached a patch to - keep it consistent with what glibc does, - make it consistent with musl libc, - make it consistent with the future POSIX standard (POSIX Issue 8). Details: glibc's implementation of ptsname_r, when it fails, returns the error code as return value AND sets errno. See https://sourceware.org/git/?p=glibc.git;a=blob;f=login/ptsname.c https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/mach/hurd/ptsname.c https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/ptsname.c musl's implementation of ptsname_r, when it fails, returns the error code but does NOT set errno. See https://git.musl-libc.org/cgit/musl/tree/src/misc/pty.c The proposal to add ptsname_r to POSIX, with text "If successful, the ptsname_r( ) function shall return zero. Otherwise, an error number shall be returned to indicate the error." has been accepted for inclusion in POSIX Issue 8. http://austingroupbugs.net/view.php?id=508 Therefore a portable program should look at the return value from ptsname_r, NOT the errno value. The current text in the man page suggests to look at the errno value, which is wrong (because of musl libc) and not future-proof (because of future POSIX). Bruno
diff --git a/man3/ptsname.3 b/man3/ptsname.3 index 394138b..0137fe7 100644 --- a/man3/ptsname.3 +++ b/man3/ptsname.3 @@ -63,12 +63,9 @@ On failure, NULL is returned. On success, .BR ptsname_r () returns 0. -On failure, a nonzero value is returned -and -.I errno -is set to indicate the error. -.\" In fact the errno value is also returned as the function -.\" result -- MTK, Dec 04 +On failure, an error number is returned to indicate the error. +.\" In glibc, the error number is not only returned as the return value +.\" but also stored in errno. But this is not true for musl libc. .SH ERRORS .TP .B EINVAL
