Add errno program

1 files changed, 74 insertions, 0 deletions

diff --git a/errno.c b/errno.c
new file mode 100644
index 0000000..aa5307b
--- /dev/null
+++ b/errno.c
@@ -0,0 +1,74 @@
+#include <ctype.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+static struct {
+    const char *name;
+    int code;
+} errnos[] = {
+    #include "errnos.h"
+};
+static const int num_errnos = sizeof(errnos) / sizeof(errnos[0]);
+
+
+static void
+report(const char *name, int code)
+{
+    printf("%s %d %s\n", name, code, strerror(code));
+}
+
+
+static bool
+report_from_name(const char *name)
+{
+    int i;
+    for (i = 0; i < num_errnos; ++i) {
+        if (strcasecmp(errnos[i].name,  name) == 0) {
+            report(errnos[i].name, errnos[i].code);
+            return true;
+        }
+    }
+    return false;
+}
+
+
+static bool
+report_from_code(int code)
+{
+    int i;
+    for (i = 0; i < num_errnos; ++i) {
+        if (errnos[i].code == code) {
+            report(errnos[i].name, code);
+            return true;
+        }
+    }
+    return false;
+}
+
+
+int 
+main(int argc, char **argv)
+{
+    int i;
+    int exit_code;
+    
+    exit_code = EXIT_SUCCESS;
+    for (i = 1; i < argc; ++i) {
+        const char *arg = argv[i];
+        if (toupper(arg[0]) == 'E') {
+            if (!report_from_name(arg))
+                exit_code = EXIT_FAILURE;
+        } else if (isdigit(arg[0])) {
+            if (!report_from_code(atoi(arg)))
+                exit_code = EXIT_FAILURE;
+        } else {
+            fprintf(stderr, "ERROR: Not understood: %s\n", arg);
+            exit_code = EXIT_FAILURE;
+        }
+    }
+    return exit_code;
+}