--- /dev/null
+// Compare given libc name and version number to system name and version.
+
+// Returns
+// - 0 if the libc name matches is at least the minimum version (if given).
+// - 1 if the libc name doesn't match or the version is lower than requested.
+// - 2 if the requested libc name isn't recognised.
+// - 3 if there was a usage error (it also prints an error message).
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef __GLIBC__
+#include <gnu/libc-version.h>
+#endif
+
+#define False 0
+#define True 1
+typedef int Bool;
+
+/* Assumes the versions are x.y.z, with y and z optional. */
+static Bool matches_version(char *min_version) {
+ int a1=0, a2=0, a3=0, g1=0, g2=0, g3=0; // 'a' = actual; 'g' = given
+ const char *aversion;
+
+ if (min_version == NULL) return True; // no version specified
+
+ // get actual version number
+#ifdef __GLIBC__
+ aversion = gnu_get_libc_version();
+#else
+ aversion = "unknown";
+#endif
+ // We expect at least one number.
+ if (sscanf(aversion, "%d.%d.%d", &a1, &a2, &a3) < 1) return False;
+
+ // parse given version number.
+ if (sscanf(min_version, "%d.%d.%d", &g1, &g2, &g3) < 1) return False;
+
+ if (a1 > g1) return True;
+ if (a1 < g1) return False;
+ if (a2 > g2) return True;
+ if (a2 < g2) return False;
+ if (a3 >= g3) return True;
+
+ return False;
+}
+
+static Bool go(char* libc, char *min_version)
+{
+#ifdef __GLIBC__
+ if ( 0 == strcmp( libc, "glibc" )
+ && matches_version( min_version ))
+ return True;
+#endif
+
+ return False;
+}
+
+//---------------------------------------------------------------------------
+// main
+//---------------------------------------------------------------------------
+int main(int argc, char **argv)
+{
+ if ( argc < 2 ) {
+ fprintf( stderr, "usage: libc_test <libc-name> [<min-version>]\n" );
+ exit(3); // Usage error.
+ }
+ if (go( argv[1], argv[2] )) {
+ return 0; // Matched.
+ }
+
+ if ( 0 == strcmp ( argv[1], "glibc" ) ) {
+ return 1; // Requested libc name known, but this isn't it.
+ // Or it wasn't the minimum requested version.
+ }
+ return 2; // Didn't match any known libc name.
+}