treewide: replace include guards with pragma once

An alternative to include guards using `#ifndef`, `#define` and `#endif`
is `#pragma once`. This non-standard but commonly supported directive
among C and C++ compilers, it also requires less code and does not
require the definition of a variable with risk of name conflicts. Also,
the variable definitions often deviate after file renaming and/or move.

Bonus, the use of `#pragma once` may improve compilation speed since it
is a higher-level mechanism. The compiler itself can compare filenames
or inodes without having to invoke the C preprocessor to resolve
`#ifndef` and `#endif`.

Signed-off-by: Robin Jarry <[email protected]>

Author: rjarry

api/gr_api.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_API
-#define _GR_API
+#pragma once
 
 #include <stdbool.h>
 #include <stddef.h>
@@ -68,5 +67,3 @@ struct gr_api_event {
 };
 
 int gr_api_client_event_recv(const struct gr_api_client *, struct gr_api_event **);
-
-#endif

api/gr_api_client_impl.h

@@ -3,8 +3,7 @@
 
 // This file must be included in *one* of your client application files.
 
-#ifndef _GR_API_CLIENT_IMPL
-#define _GR_API_CLIENT_IMPL
+#pragma once
 
 #include <gr_api.h>
 #include <gr_macro.h>
@@ -161,5 +160,3 @@ int gr_api_client_event_recv(const struct gr_api_client *c, struct gr_api_event
 	*event = NULL;
 	return -errno;
 }
-
-#endif

api/gr_bitops.h

@@ -1,14 +1,11 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_BITOPS
-#define _GR_BITOPS
+#pragma once
 
 #include <stdint.h>
 
 #define GR_BIT8(n) (UINT8_C(1) << (n))
 #define GR_BIT16(n) (UINT16_C(1) << (n))
 #define GR_BIT32(n) (UINT32_C(1) << (n))
 #define GR_BIT64(n) (UINT64_C(1) << (n))
-
-#endif

api/gr_clock.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2025 Robin Jarry
 
-#ifndef _GR_CLOCK
-#define _GR_CLOCK
+#pragma once
 
 #include <stdint.h>
 #include <time.h>
@@ -19,5 +18,3 @@ static inline clock_t gr_clock_us(void) {
 	struct timespec tp = gr_clock_raw();
 	return (tp.tv_sec * CLOCKS_PER_SEC) + (tp.tv_nsec / 1000);
 }
-
-#endif

api/gr_errno.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_API_ERRNO
-#define _GR_API_ERRNO
+#pragma once
 
 #include <errno.h>
 #include <stddef.h>
@@ -16,5 +15,3 @@ static inline void *errno_set_null(int errnum) {
 	errno = errnum;
 	return NULL;
 }
-
-#endif

api/gr_macro.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_MACRO
-#define _GR_MACRO
+#pragma once
 
 #include <errno.h>
 
@@ -37,5 +36,3 @@
 		}                                                                                  \
 		n += __s;                                                                          \
 	} while (0)
-
-#endif

api/gr_net_compat.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_NET_COMPAT
-#define _GR_NET_COMPAT
+#pragma once
 
 #include <limits.h>
 #include <stdint.h>
@@ -66,5 +65,3 @@ struct __attribute__((aligned(2))) rte_ether_addr {
 #define ICMP6_TYPE_ERR_PARAM_PROBLEM 4
 #define ICMP6_TYPE_ECHO_REQUEST 128
 #define ICMP6_TYPE_ECHO_REPLY 129
-
-#endif

api/gr_net_types.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_NET_TYPES
-#define _GR_NET_TYPES
+#pragma once
 
 #include <gr_errno.h>
 
@@ -136,5 +135,3 @@ static inline int ip6_net_parse(const char *s, struct ip6_net *net, bool zero_ma
 
 #define IP_ANY_RE "^(" __IPV4_RE "|" __IPV6_RE ")$"
 #define IP_ANY_NET_RE "^(" __IPV4_RE __IPV4_PREFIX_RE "|" __IPV6_RE __IPV6_PREFIX_RE "$"
-
-#endif

api/gr_string.h

@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#ifndef _GR_STRING
-#define _GR_STRING
+#pragma once
 
 #include <sched.h>
 #include <stddef.h>
@@ -17,5 +16,3 @@ int cpuset_format(char *buf, size_t len, const cpu_set_t *set);
 
 // Parse a list of CPUs (e.g. "0,1,3-9") to a cpu_set_t object.
 int cpuset_parse(cpu_set_t *set, const char *buf);
-
-#endif

cli/complete.h

@@ -1,11 +1,8 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2023 Robin Jarry
 
-#ifndef _GR_CLI_COMPLETE
-#define _GR_CLI_COMPLETE
+#pragma once
 
 #include <ecoli.h>
 
 int bash_complete(struct ec_node *cmdlist);
-
-#endif