add directory study

study/linux-travel/minix-386/estdio21.tar/estdio21/perror.c

@@ -0,0 +1,39 @@
+/*                               p e r r o r                               */
+
+#include "stdiolib.h"
+
+/*LINTLIBRARY*/
+
+void perror F1(register CONST char *, s)
+
+{
+#define MAXDIGS	11			/* maximum digits in unknown */
+  static char unknown[] = {'U','n','k','n','o','w','n',' ',
+		           'e','r','r','o','r',' ',
+		           '0','0','0','0','0','0','0','0','0','0','0',0};
+  int errnum;				/* error number */
+  char *errdesc;			/* error description */
+
+  errnum = errno;
+
+  if (__Zerr != NULL)
+    (void) FFLUSH(__Zerr);
+
+  if (s != NULL && *s != 0) {
+    (void) __iowrite(STDERR_FILENO, (char *) s, strlen(s));
+    (void) __iowrite(STDERR_FILENO, ": ", 2);
+  }
+  if (errnum > 0 && errnum < sys_nerr)
+    errdesc = sys_errlist[errnum];
+  else {
+    errdesc = &unknown[sizeof(unknown)-MAXDIGS-1];
+    if (errnum < 0) {
+      *errdesc++ = '-';
+      errnum = -errnum;
+    }
+    *__utoa(errdesc, (unsigned) errnum, 1) = 0;
+    errdesc = &unknown[0];
+  }
+  (void) __iowrite(STDERR_FILENO, errdesc, strlen(errdesc));
+  (void) __iowrite(STDERR_FILENO, "\n", 1);
+}