diff --git a/bp.c b/bp.c
index 02345f1..3195885 100644
--- a/bp.c
+++ b/bp.c
@@ -342,8 +342,8 @@ __attribute__((nonnull(2)))
 static int process_git_files(def_t *defs, pat_t *pattern, int argc, char *argv[])
 {
     int fds[2];
-    check_nonnegative(pipe(fds), "Failed to create pipe");
-    pid_t child = check_nonnegative(fork(), "Failed to fork");
+    require(pipe(fds), "Failed to create pipe");
+    pid_t child = require(fork(), "Failed to fork");
     if (child == 0) {
         const char **git_args = new(char*[3+argc+1]);
         int g = 0;
@@ -351,20 +351,20 @@ static int process_git_files(def_t *defs, pat_t *pattern, int argc, char *argv[]
         git_args[g++] = "ls-files";
         git_args[g++] = "-z";
         while (*argv) git_args[g++] = *(argv++);
-        check_nonnegative(dup2(fds[STDOUT_FILENO], STDOUT_FILENO), "Failed to hook up pipe to stdout");
-        check_nonnegative(close(fds[STDIN_FILENO]), "Failed to close read end of pipe");
+        require(dup2(fds[STDOUT_FILENO], STDOUT_FILENO), "Failed to hook up pipe to stdout");
+        require(close(fds[STDIN_FILENO]), "Failed to close read end of pipe");
         (void)execvp("git", (char**)git_args);
         _exit(EXIT_FAILURE);
     }
-    check_nonnegative(close(fds[STDOUT_FILENO]), "Failed to close write end of pipe");
-    FILE *fp = check_nonnull(fdopen(fds[STDIN_FILENO], "r"), "Could not open pipe file descriptor");
+    require(close(fds[STDOUT_FILENO]), "Failed to close write end of pipe");
+    FILE *fp = require(fdopen(fds[STDIN_FILENO], "r"), "Could not open pipe file descriptor");
     char *path = NULL;
     size_t path_size = 0;
     int found = 0;
     while (getdelim(&path, &path_size, '\0', fp) > 0)
         found += process_file(defs, path, pattern);
     if (path) delete(&path);
-    check_nonnegative(fclose(fp), "Failed to close read end of pipe");
+    require(fclose(fp), "Failed to close read end of pipe");
     int status;
     while (waitpid(child, &status, 0) != child) continue;
     if (!((WIFEXITED(status) == 1) && (WEXITSTATUS(status) == 0)))
@@ -450,7 +450,7 @@ int main(int argc, char *argv[])
             if (after_spaces(p->end, true) < arg_file->end) file_err(arg_file, p->end, arg_file->end, "Failed to compile this part of the argument");
             pattern = chain_together(arg_file, pattern, p);
         } else if (FLAG("-w")     || FLAG("--word")) {
-            check_nonnegative(asprintf(&flag, "\\|%s\\|", flag), "Could not allocate memory");
+            require(asprintf(&flag, "\\|%s\\|", flag), "Could not allocate memory");
             file_t *arg_file = spoof_file(&loaded_files, "<word pattern>", flag, -1);
             delete(&flag);
             pat_t *p = bp_stringpattern(arg_file, arg_file->start);
@@ -505,10 +505,10 @@ int main(int argc, char *argv[])
     int signals[] = {SIGTERM, SIGINT, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGSEGV, SIGTSTP};
     struct sigaction sa = {.sa_handler = &sig_handler, .sa_flags = (int)(SA_NODEFER | SA_RESETHAND)};
     for (size_t i = 0; i < sizeof(signals)/sizeof(signals[0]); i++)
-        check_nonnegative(sigaction(signals[i], &sa, NULL), "Failed to set signal handler");
+        require(sigaction(signals[i], &sa, NULL), "Failed to set signal handler");
 
     // Handle exit() calls gracefully:
-    check_nonnegative(atexit(&cleanup), "Failed to set cleanup handler at exit");
+    require(atexit(&cleanup), "Failed to set cleanup handler at exit");
 
     // No need for these caches anymore:
     for (file_t *f = loaded_files; f; f = f->next)
diff --git a/files.c b/files.c
index 969cc2d..79d2a03 100644
--- a/files.c
+++ b/files.c
@@ -116,7 +116,7 @@ file_t *load_file(file_t **files, const char *filename)
 
   finished_loading:
     if (fd != STDIN_FILENO)
-        check_nonnegative(close(fd), "Failed to close file");
+        require(close(fd), "Failed to close file");
 
     populate_lines(f);
     if (files != NULL) {
@@ -177,7 +177,7 @@ void destroy_file(file_t **at_f)
         delete(&f->allocated);
 
     if (f->mmapped) {
-        check_nonnegative(munmap(f->mmapped, (size_t)(f->end - f->mmapped)),
+        require(munmap(f->mmapped, (size_t)(f->end - f->mmapped)),
                           "Failure to un-memory-map some memory");
         f->mmapped = NULL;
     }
diff --git a/utils.c b/utils.c
index 5ecbcf1..cb0719c 100644
--- a/utils.c
+++ b/utils.c
@@ -128,36 +128,6 @@ char unescapechar(const char *escaped, const char **end)
     return (char)ret;
 }
 
-//
-// If the given argument is NULL, print the error message and exit with
-// failure. Otherwise return the given argument.
-//
-void *check_nonnull(void *p, const char *err_msg, ...)
-{
-    if (p == NULL) {
-        va_list args;
-        va_start(args, err_msg);
-        verr(EXIT_FAILURE, err_msg, args);
-        va_end(args);
-    }
-    return p;
-}
-
-//
-// If the given argument is negative, print the error message and exit with
-// failure. Otherwise return the given argument.
-//
-int check_nonnegative(int i, const char *err_msg, ...)
-{
-    if (i < 0) {
-        va_list args;
-        va_start(args, err_msg);
-        verr(EXIT_FAILURE, err_msg, args);
-        va_end(args);
-    }
-    return i;
-}
-
 //
 // Case-insensitive memory comparison
 //
diff --git a/utils.h b/utils.h
index b645817..04df47a 100644
--- a/utils.h
+++ b/utils.h
@@ -4,6 +4,8 @@
 #ifndef UTILS__H
 #define UTILS__H
 
+#include <err.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -16,10 +18,34 @@
 #define S2(x) S1(x)
 #define __LOCATION__ __FILE__ ":" S2(__LINE__)
 
+#define DEFINE_CHECK_TYPE(t, name, var, expr) \
+static inline t _check_##name(t var, const char *fmt, ...) { \
+    if (!(expr)) {\
+        va_list args;\
+        va_start(args, fmt);\
+        verrx(1, fmt, args);\
+        va_end(args);\
+    }\
+    return var;\
+}
+DEFINE_CHECK_TYPE(void*, ptr, p, p);
+DEFINE_CHECK_TYPE(int, int, i, i >= 0);
+DEFINE_CHECK_TYPE(ssize_t, ssize_t, i, i >= 0);
+DEFINE_CHECK_TYPE(char, char, c, c);
+DEFINE_CHECK_TYPE(_Bool, bool, b, b);
+
+#define PP_ARG_N(_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,_13,_14,_15,_16,_17,_18,_19,_20,_21,_22,_23,_24,_25,_26,_27,_28,_29,_30,_31,N,...) N
+#define PP_NARG(...) PP_ARG_N(__VA_ARGS__,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0)
+
+#define _require_fmt(e, ...) _Generic((e), _Bool: _check_bool, int: _check_int, ssize_t: _check_ssize_t, char: _check_char, void*: _check_ptr, default: _check_ptr)((e), ""__VA_ARGS__)
+#define require(e, ...) (PP_NARG(e,##__VA_ARGS__) > 1 ? _require_fmt((e), __LOCATION__": "__VA_ARGS__) : _require_fmt((e), __LOCATION__": `%s` failed", #e))
+#define require_true(e, ...) (PP_NARG(e,##__VA_ARGS__) > 1 ? _require_fmt((_Bool)(e), __LOCATION__": "__VA_ARGS__) : _require_fmt((_Bool)(e), __LOCATION__": `%s` is not true", #e))
+
+#define new(t) _check_ptr(calloc(1, sizeof(t)), "`new(" #t ")` allocation failure")
+#define checked_strdup(s) _check_ptr(strdup(s), "`checked_strdup(" #s ")` allocation failure")
+#define grow(arr,n) _check_ptr(realloc(arr,sizeof(arr[0])*(n)), "`grow(" #arr ", " #n ")` allocation failure")
+
 #define streq(a, b) (strcmp(a, b) == 0)
-#define new(t) check_nonnull(calloc(1, sizeof(t)), __LOCATION__ ": `new(" #t ")` allocation failure")
-#define checked_strdup(s) check_nonnull(strdup(s), __LOCATION__ ": `checked_strdup(" #s ")` allocation failure")
-#define grow(arr,n) check_nonnull(realloc(arr,sizeof(arr[0])*(n)), __LOCATION__ ": `groaw(" #arr ", " #n ")` allocation failure")
 
 __attribute__((nonnull(1)))
 char unescapechar(const char *escaped, const char **end);
@@ -31,9 +57,6 @@ __attribute__((nonnull))
 bool matchchar(const char **str, char c, bool skip_nl);
 __attribute__((nonnull))
 bool matchstr(const char **str, const char *target, bool skip_nl);
-__attribute__((returns_nonnull))
-void *check_nonnull(void *p, const char *err_msg, ...);
-int check_nonnegative(int i, const char *err_msg, ...);
 __attribute__((nonnull))
 int memicmp(const void *s1, const void *s2, size_t n);
 __attribute__((nonnull))