From 35864dc694316712d137a06d8100ebdd2eb57f09 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@member.fsf.org>
Date: Mon, 21 Dec 2015 16:19:58 +0100
Subject: add getenv
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Signed-off-by: Mattias Andrée <maandree@member.fsf.org>
---
src/stdlib/getenv.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
create mode 100644 src/stdlib/getenv.c
(limited to 'src')
diff --git a/src/stdlib/getenv.c b/src/stdlib/getenv.c
new file mode 100644
index 0000000..e0302f1
--- /dev/null
+++ b/src/stdlib/getenv.c
@@ -0,0 +1,73 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+
+
+/**
+ * The process's environment variables.
+ */
+extern char** environ;
+
+
+
+/**
+ * This function returns the value assoicated with a
+ * specified environment variable.
+ *
+ * Portable program must not check `errno`. No errors
+ * are defined by POSIX.
+ *
+ * @etymology (Get) the value of an (env)ironment variable!
+ *
+ * @param name The name of the sought environment variable.
+ * Must not be `NULL`.
+ * @return The value of the environment variable.
+ * `NULL` on error, or if not found. This
+ * pointer is subpointer, and must not be
+ * modified except for in-place changes.
+ *
+ * @throws 0 No such environment variable found.
+ * This is a slibc extensions.
+ * @throws EINVAL `name` is `NULL` (must not be the case), empty,
+ * or contains a '='. This is a slibc extensions.
+ *
+ * @since Always.
+ */
+char* getenv(const char* name)
+{
+ size_t i, n;
+
+ if (!name || !*name || strchr(name, '='))
+ return errno = EINVAL, NULL;
+
+ errno = 0;
+ if (environ == NULL)
+ return NULL;
+
+ n = strlen(name);
+ for (i = 0; environ[i] != NULL; i++)
+ if (!strncmp(name, environ[i], n))
+ if (environ[i][n] == '=')
+ return environ[i] + n + 1;
+
+ return NULL;
+}
+
--
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