Add libsimple_eprintf_preprint and libsimple_eprintf_postprint

Signed-off-by: Mattias Andrée <maandree@kth.se>

9 files changed, 129 insertions, 15 deletions

diff --git a/libsimple.c b/libsimple.c
index 93f7357..3026160 100644
--- a/libsimple.c
+++ b/libsimple.c
@@ -3,9 +3,6 @@
 #ifndef TEST
 
 
-int libsimple_default_failure_exit = 1;
-
-
 #else
 #include "test.h"
 
diff --git a/libsimple.h b/libsimple.h
index 2c39098..4663eb4 100644
--- a/libsimple.h
+++ b/libsimple.h
@@ -47,14 +47,6 @@
 #endif
 
 
-/**
- * Exit value for `libsimple_eprintf`
- * 
- * Default value is 1
- */
-extern int libsimple_default_failure_exit;
-
-
 #include "libsimple/printf.h"
 #include "libsimple/definitions.h"
 #include "libsimple/memalloc.h"
diff --git a/libsimple/printf.h b/libsimple/printf.h
index 9b6253c..cf7192e 100644
--- a/libsimple/printf.h
+++ b/libsimple/printf.h
@@ -2,6 +2,40 @@
 
 
 /**
+ * Exit value for `libsimple_eprintf`
+ * 
+ * Default value is 1
+ */
+extern int libsimple_default_failure_exit;
+
+
+/**
+ * Unless `NULL`, called from `libsimple_vweprintf`
+ * before the `eprintf`-family of functions print
+ * the message.
+ * 
+ * `errno` is not necessarily the same value as
+ * it was when `libsimple_vweprintf` was called.
+ * 
+ * Default value is `NULL`
+ */
+extern void (*libsimple_eprintf_preprint)(void);
+
+
+/**
+ * Unless `NULL`, called from `libsimple_vweprintf`
+ * after the `eprintf`-family of functions print
+ * the message.
+ * 
+ * `errno` is not necessarily the same value as
+ * it was when `libsimple_vweprintf` was called.
+ * 
+ * Default value is `NULL`
+ */
+extern void (*libsimple_eprintf_postprint)(void);
+
+
+/**
  * Version of `printf` that allocates, on the heap, a
  * sufficiently large string and writes the output to it
  * 
diff --git a/man/libsimple_eprintf_postprint.3 b/man/libsimple_eprintf_postprint.3
new file mode 120000
index 0000000..39ff456
--- /dev/null
+++ b/man/libsimple_eprintf_postprint.3
@@ -0,0 +1 @@
+libsimple_vweprintf.3
\ No newline at end of file
diff --git a/man/libsimple_eprintf_preprint.3 b/man/libsimple_eprintf_preprint.3
new file mode 120000
index 0000000..39ff456
--- /dev/null
+++ b/man/libsimple_eprintf_preprint.3
@@ -0,0 +1 @@
+libsimple_vweprintf.3
\ No newline at end of file
diff --git a/man/libsimple_vweprintf.3 b/man/libsimple_vweprintf.3
index ca241b1..06d339d 100644
--- a/man/libsimple_vweprintf.3
+++ b/man/libsimple_vweprintf.3
@@ -6,6 +6,8 @@ libsimple_vweprintf \- print an error message
 #include <libsimple.h>
 
 extern int libsimple_default_failure_exit;
+extern void (*libsimple_eprint_preprint)(void);
+extern void (*libsimple_eprint_postprint)(void);
 
 void libsimple_vweprintf(const char *\fIfmt\fP, va_list \fIap\fP);
 static inline void libsimple_weprintf(const char *\fIfmt\fP, ...);
@@ -74,7 +76,7 @@ does not start with
 the output is preffixed with
 .nf
 
-	\fB\(dq%s: \(dq, \fPIargv0\fP
+	\fB\(dq%s: \(dq, \fP\fIargv0\fP
 .fi
 .PP
 The
@@ -110,6 +112,45 @@ functions that terminate the process by calling
 the exit value of the process will be
 .IR libsimple_default_failure_exit (3),
 which is 1 by default.
+.PP
+The
+.BR libsimple_vweprintf (),
+.BR libsimple_weprintf (),
+.BR libsimple_venprintf (),
+.BR libsimple_enprintf (),
+.BR libsimple_veprintf (),
+and
+.BR libsimple_eprintf ()
+functions call
+.I libsimple_eprint_preprint
+unless it is
+.B NULL
+before they print the message, after printing
+the message they call
+.I libsimple_eprint_postprint
+unless it is
+.BR NULL .
+The
+.I libsimple_eprint_preprint
+and
+.I libsimple_eprint_postprint
+variables are
+.B NULL
+byte default.
+.I errno
+may have a different value from when the
+.BR libsimple_vweprintf (),
+.BR libsimple_weprintf (),
+.BR libsimple_venprintf (),
+.BR libsimple_enprintf (),
+.BR libsimple_veprintf (),
+or
+.BR libsimple_eprintf ()
+function called when
+.I libsimple_eprint_preprint
+or
+.I libsimple_eprint_postprint
+is called.
 .SH RETURN VALUE
 None.
 .SH ERRORS
diff --git a/test.c b/test.c
index 80b7ad7..f785483 100644
--- a/test.c
+++ b/test.c
@@ -294,6 +294,13 @@ fprintf(FILE *restrict stream, const char *restrict format, ...)
 int
 vfprintf(FILE *restrict stream, const char *restrict format, va_list ap)
 {
+	return test_vfprintf(stream, format, ap);
+}
+
+
+int
+test_vfprintf(FILE *restrict stream, const char *restrict format, va_list ap)
+{
 	size_t old_alloc_fail_in = alloc_fail_in;
 	va_list ap2;
 	int r;
diff --git a/test.h b/test.h
index 3aba488..29e6f13 100644
--- a/test.h
+++ b/test.h
@@ -83,3 +83,15 @@ size_t get_pagesize(void);
 size_t round_up(size_t);
 int have_custom_malloc(void); /* return 0 if run under valgrind(1) */
 struct allocinfo *get_allocinfo(void *);
+
+
+int test_vfprintf(FILE *restrict stream, const char *restrict format, va_list ap);
+
+static inline int
+test_fprintf(FILE *restrict stream, const char *restrict format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	return test_vfprintf(stream, format, ap);
+	va_end(ap);
+}
diff --git a/vweprintf.c b/vweprintf.c
index 96a82a7..9263d52 100644
--- a/vweprintf.c
+++ b/vweprintf.c
@@ -6,6 +6,11 @@
 extern char *argv0;
 
 
+int libsimple_default_failure_exit = 1;
+void (*libsimple_eprintf_preprint)(void) = NULL;
+void (*libsimple_eprintf_postprint)(void) = NULL;
+
+
 void
 libsimple_vweprintf(const char *fmt, va_list ap)
 {
@@ -44,6 +49,8 @@ libsimple_vweprintf(const char *fmt, va_list ap)
 		suffix1 = "\n";
 	}
 
+	if (libsimple_eprintf_preprint)
+		libsimple_eprintf_preprint();
 	if (message) {
 		/* This is to avoid mangling when multiple processes are writting. */
 		fprintf(stderr, "%s%s%s%s%s%s", prefix1, prefix2, message, suffix1, suffix2, suffix3);
@@ -52,6 +59,8 @@ libsimple_vweprintf(const char *fmt, va_list ap)
 		vfprintf(stderr, fmt, ap);
 		fprintf(stderr, "%s%s%s", suffix1, suffix2, suffix3);
 	}
+	if (libsimple_eprintf_postprint)
+		libsimple_eprintf_postprint();
 
 	errno = saved_errno;
 }
@@ -64,6 +73,18 @@ libsimple_vweprintf(const char *fmt, va_list ap)
 # pragma GCC diagnostic ignored "-Wformat-zero-length"
 #endif
 
+static void
+preprint(void)
+{
+	test_fprintf(stderr, "pre\n");
+}
+
+static void
+postprint(void)
+{
+	test_fprintf(stderr, "post\n");
+}
+
 int
 main(void)
 {
@@ -92,15 +113,23 @@ main(void)
 		for (j = 0; j < 3; j++) {
 			T("%s%s%s\n", "abc", "123", "xyz");
 			assert_stderr("%s%s\n", prefix, "abc123xyz");
+			libsimple_eprintf_preprint = preprint;
 			T("%s%s%s\n", "abc", "123", "\n");
-			assert_stderr("%s%s\n", prefix, "abc123\n");
+			assert_stderr("pre\n%s%s\n", prefix, "abc123\n");
+			libsimple_eprintf_preprint = NULL;
+			libsimple_eprintf_postprint = postprint;
 			T("%s%s%s", "abc", "123", "xyz");
-			assert_stderr("%s%s\n", prefix, "abc123xyz");
+			assert_stderr("%s%s\npost\n", prefix, "abc123xyz");
+			libsimple_eprintf_postprint = NULL;
 			T("%s%s%s", "abc", "123", "\n");
 			assert_stderr("%s%s\n", prefix, "abc123\n");
 			errno = EDOM;
+			libsimple_eprintf_preprint = preprint;
+			libsimple_eprintf_postprint = postprint;
 			T("%s%s%s:", "abc", "123", "\n");
-			assert_stderr("%s%s: %s\n", prefix, "abc123\n", strerror(EDOM));
+			assert_stderr("pre\n%s%s: %s\npost\n", prefix, "abc123\n", strerror(EDOM));
+			libsimple_eprintf_preprint = NULL;
+			libsimple_eprintf_postprint = NULL;
 			errno = ERANGE;
 			T("%s%s%s:", "abc", "123", "\n");
 			assert_stderr("%s%s: %s\n", prefix, "abc123\n", strerror(ERANGE));