Created attachment 11437 [details]
test .c file

Created attachment 11438 [details]
CORRECT ccache log file

proper ccache log file

That's strange. It's most likely related to unexpected behavior of syscalls/libc on QNX.

Would it be possible for you to run a tool similar to strace (syscall tracer) to see which syscalls ccache makes and what the OS gives back as results?

If you're interested in debugging ccache, it seems that the create_parent_dirs function in util.c for some reason doesn't work on QNX.

Some by-the-way comments:

1. CCACHE_VERBOSE has no effect for ccache 3.*.
2. Setting PATH=/opt/ccache/tools/:$PATH on the same commandline as the compiler has no effect (unless QNX's /bin/sh is a very strange shell).

I've added some debug in create_parent_dirs() function, but today this error has gone for some reason, and 3.2.3 works well. I'll keep to watch on it.

As for PATH before compiler, that's common trick both for QNX and Linux. I usually do this way instead of export'ing variables in case they are needed just for one time/few times. 
# PATH=/opt/ccache/tools/:$PATH i486-pc-nto-qnx6.5.0-gcc - will run ccache thru symlink
# i486-pc-nto-qnx6.5.0-gcc - will run native compiler (/usr/qnx650/host/...)

> As for PATH before compiler, that's common trick both for QNX and Linux.

Ah, my bad.

> I've added some debug in create_parent_dirs() function, but today this
> error has gone for some reason, and 3.2.3 works well. I'll keep to watch
> on it.

Great, that would be appreciated. I'm not able to test it on QNX myself.

Any success in debugging this issue?

(In reply to Joel Rosdahl from comment #6)
Unfortunately, the problem has not taken place since first time. In fact, i don't use ccache under QNX very often (generally preferring cross-compiling, so using it under Linux).

Finally, found the cause for this. It't due to QNX's mkstemp(char *template) function's behavior (unit.c:1181): it may change contents of template char array if it fails with ENOENT trying to create temporary file in non-existent directory (what it actually does - it leaves only path to that non-existent directory in 'template' array, cutting the rest). Linux and, probably, some other OSes' mkstemp() leave template unchanged even in case of failure. Seems it is not covered by any standards like POSIX or its XSI extensions, so we cannot rely on template's contents after mkstemp() failure. Probably it would be better to use a copy of template, someting like:

util.c:1181
--- cut ---
    char *tempdup = strdup(template);
    int fd = mkstemp(tempdup);
    free(tempdup);
    if (fd == -1 && errno == ENOENT) {
--- cut ---

Or probably better like this (to avoid unnecessary alloc/free in case of success):

---cut---
int
create_tmp_fd(char **fname)
{
        char *tmpstr = tmp_string();
        char *template = format("%s.%s", *fname, tmpstr);
        int fd = mkstemp(template);
        if (fd == -1 && errno == ENOENT) {
                reformat(&template, "%s.%s", *fname, tmpstr);
                if (create_parent_dirs(template) != 0) {
                        fatal("Failed to create directory %s: %s",
                              dirname(template), strerror(errno));
                }
                fd = mkstemp(template);
        }
        if (fd == -1) {
                reformat(&template, "%s.%s", *fname, tmpstr);
                fatal("Failed to create file %s: %s", template, strerror(errno));
        }
--- cut ---

Thanks for the investigation!

What do you think about this fix?

--- a/util.c
+++ b/util.c
@@ -1180,15 +1180,16 @@ create_tmp_fd(char **fname)
        char *template = format("%s.%s", *fname, tmp_string());
        int fd = mkstemp(template);
        if (fd == -1 && errno == ENOENT) {
-               if (create_parent_dirs(template) != 0) {
+               if (create_parent_dirs(*fname) != 0) {
                        fatal("Failed to create directory %s: %s",
-                             dirname(template), strerror(errno));
+                             dirname(*fname), strerror(errno));
                }
                reformat(&template, "%s.%s", *fname, tmp_string());
                fd = mkstemp(template);
        }
        if (fd == -1) {
-               fatal("Failed to create file %s: %s", template, strerror(errno));
+               fatal("Failed to create temporary file for %s: %s",
+                     *fname, strerror(errno));
        }
 
 #ifndef _WIN32

Igor Rondarev: Have you had time to try out my proposal?

Sorry, i've been extremely busy. I guess it should work perfectly, but this part of code

        if (fd == -1) {
-               fatal("Failed to create file %s: %s", template, strerror(errno));
+               fatal("Failed to create temporary file for %s: %s",
+                     *fname, strerror(errno))

will print directory name in case of failure, not a file name. So probably it make sense to patch only this part:
--- a/util.c
+++ b/util.c
@@ -1180,15 +1180,16 @@ create_tmp_fd(char **fname)
        char *template = format("%s.%s", *fname, tmp_string());
        int fd = mkstemp(template);
        if (fd == -1 && errno == ENOENT) {
-               if (create_parent_dirs(template) != 0) {
+               if (create_parent_dirs(*fname) != 0) {
                        fatal("Failed to create directory %s: %s",
-                             dirname(template), strerror(errno));
+                             dirname(*fname), strerror(errno));
                }
                reformat(&template, "%s.%s", *fname, tmp_string());
                fd = mkstemp(template);

> I guess it should work perfectly, but this part of code [...] will print
> directory name in case of failure, not a file name. So probably it make
> sense to patch only this part: [...]

Nope, it will print a filename (*fname). I did that intentionally after I made the observation that the content of the template is undefined for other errnos as well (for instance EEXIST) after reading my system's man page.

Fixed in 07a529dfeb452cf6bb77b5a317539eeda54b40fd.

Included in 3.2.5.