Import all system definitions of errno including their string representations, then layer our error definitions on top of that

CMakeLists.txt

@@ -7,10 +7,27 @@ include(CMakePackageConfigHelpers)
 set(AKERR_USE_STDLIB 1 CACHE BOOL "Use the C standard library")
 set(akerror_install_cmakedir "${CMAKE_INSTALL_LIBDIR}/cmake/akerror")
 
+set(SCRIPT ${CMAKE_SOURCE_DIR}/scripts/generrno.sh)
+set(INFILE ${CMAKE_SOURCE_DIR}/include/akerror.tmpl.h)
+set(OUTFILES ${CMAKE_SOURCE_DIR}/src/errno.c ${CMAKE_SOURCE_DIR}/include/akerror.h)
+add_custom_command(
+  OUTPUT ${OUTFILES}
+  COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_SOURCE_DIR}
+  COMMAND /usr/bin/env bash ${SCRIPT} ${CMAKE_SOURCE_DIR}
+  DEPENDS ${SCRIPT} ${INFILE}
+  VERBATIM
+)
+
+set_source_files_properties(src/errno.c PROPERTIES GENERATED TRUE)
+
+add_custom_target(generrno DEPENDS src/errno.c)
+
 find_package(PkgConfig REQUIRED)
 add_library(akerror STATIC
   src/error.c
+  src/errno.c
 )
+add_dependencies(akerror generrno)
 
 target_compile_definitions(akerror
     PUBLIC AKERR_USE_STDLIB=${AKERR_USE_STDLIB}

README.md

@@ -62,13 +62,14 @@ Any function which uses the `PREPARE_ERROR` macro should have a return type of `
 
 The library uses integer values to specify error codes inside of its context. These integer return codes are defined in `akerror.h` in the form of `AKERR_xxxxx` where `xxxxx` is the name of the error code in question. See `akerror.h` for a list of defined errors and their descriptions. 
 
-You can define additional error types by defining additional `AKERR_xxxxx` values. Error values up to 127 are reserved by the library, so begin your error values at 128. Define a human-friendly name for the error with the `error_name_for_status` method:
+You can define additional error types by defining additional `AKERR_xxxxx` values. Error values up to 255 are reserved by the library (`AKERR_xxxxx` begins where `errno` stops), so please begin your error values at 256. When you add additional error codes, you need to define `-DAKERR_MAX_ERR_VALUE=n` to the compiler, where `n` is the maximum error code you have defined. If you define custom error codes, `AKERR_MAX_ERR_VALUE` must be >= 256 or the compiler will throw an error.
+
+Define a human-friendly name for the error with the `error_name_for_status` method somewhere in your code's initialization before the error may be used:
 
 ```c
 error_name_for_status(129, "Some Error Code Description")
 ```
 
-When you add additional error codes, you need to define `-DAKERR_MAX_ERR_VALUE=n` to the compiler, where `n` is the maximum error code you have defined.
 
 # Installation
 
@@ -78,6 +79,14 @@ cmake --build build
 cmake --install build
 ```
 
+## Templating and autogenerated code
+
+The build process relies upon `scripts/generrno.sh` which performs the following:
+
+1. Executes `errno --list` and gathers up the output
+1. Templates `include/akerror.tmpl.h` into `include/akerror.h` to set the `AKERR_LAST_ERRNO_VALUE` equal to the highest integer defined by `errno`
+2. Generates `src/errno.c` which contains a function called by `akerr_init` which initializes all of the status names for the previously defined values of `errno`.
+
 ## Dependencies
 
 This library depends upon `stdlib`. If you don't want to link against stdlib, you must modify the library code to include headers and link against a library that provides the following:
@@ -172,7 +181,7 @@ ATTEMPT {
 
 `PROCESS(errctx) { ... }` is the block within which you will handle any errors that were caught inside of the `ATTEMPT` block. See "Handling Errors" below.
 
-`FINISH(errctx, true)` terminates the attempt operation. The `FINISH` macro takes two arguments: the name of the akerr_ErrorContext, and a boolean regarding whether or not to pass unhandled errors up to the calling function. Unless you are inside of your `main()` method, this should be true. Inside of your `main()` method, call `FINISH_NORETURN(errctx)` instead.
+`FINISH(errctx, true)` terminates the attempt operation. The `FINISH` macro takes two arguments: the name of the akerr_ErrorContext, and a boolean regarding whether or not to pass unhandled errors up to the calling function. Unless you are inside of your `main()` method, this should be true. Inside of your `main()` method, call `FINISH_NORExbTURN(errctx)` instead.
 
 
 # Capturing errors

include/akerror.tmpl.h

@@ -14,23 +14,27 @@
 #define AKERR_MAX_ERROR_FUNCTION_LENGTH                    128
 #define AKERR_MAX_ERROR_STACKTRACE_BUF_LENGTH              2048
 
-#define AKERR_NULLPOINTER           1
+#define AKERR_LAST_ERRNO_VALUE      AKERR_LAST_ERRNO_VALUE_SED
-#define AKERR_OUTOFBOUNDS           2
+
-#define AKERR_API                   3
+#define AKERR_NULLPOINTER           (AKERR_LAST_ERRNO_VALUE + 1)
-#define AKERR_ATTRIBUTE             4
+#define AKERR_OUTOFBOUNDS           (AKERR_LAST_ERRNO_VALUE + 2)
-#define AKERR_TYPE                  5
+#define AKERR_API                   (AKERR_LAST_ERRNO_VALUE + 3)
-#define AKERR_KEY                   6                    
+#define AKERR_ATTRIBUTE             (AKERR_LAST_ERRNO_VALUE + 4)
-#define AKERR_HEAP                  7
+#define AKERR_TYPE                  (AKERR_LAST_ERRNO_VALUE + 5)
-#define AKERR_INDEX                 8
+#define AKERR_KEY                   (AKERR_LAST_ERRNO_VALUE + 6)                   
-#define AKERR_FORMAT                9
+#define AKERR_HEAP                  (AKERR_LAST_ERRNO_VALUE + 7)
-#define AKERR_IO                    10
+#define AKERR_INDEX                 (AKERR_LAST_ERRNO_VALUE + 8)
-#define AKERR_REGISTRY              11
+#define AKERR_FORMAT                (AKERR_LAST_ERRNO_VALUE + 9)
-#define AKERR_VALUE                 12
+#define AKERR_IO                    (AKERR_LAST_ERRNO_VALUE + 10)
-#define AKERR_BEHAVIOR              13
+#define AKERR_REGISTRY              (AKERR_LAST_ERRNO_VALUE + 11)
-#define AKERR_RELATIONSHIP          14
+#define AKERR_VALUE                 (AKERR_LAST_ERRNO_VALUE + 12)
+#define AKERR_BEHAVIOR              (AKERR_LAST_ERRNO_VALUE + 13)
+#define AKERR_RELATIONSHIP          (AKERR_LAST_ERRNO_VALUE + 14)
 
 #ifndef AKERR_MAX_ERR_VALUE
-#define AKERR_MAX_ERR_VALUE 14
+#define AKERR_MAX_ERR_VALUE (AKERR_LAST_ERRNO_VALUE + 14)
+#elif AKERR_MAX_ERR_VALUE < 256
+#error user-defined AKERR_MAX_ERR_VALUE must be >= 256
 #endif
 
 extern char __AKERR_ERROR_NAMES[AKERR_MAX_ERR_VALUE+1][AKERR_MAX_ERROR_NAME_LENGTH];
@@ -69,6 +73,8 @@ char *akerr_name_for_status(int status, char *name);
 void akerr_init();
 void akerr_default_handler_unhandled_error(akerr_ErrorContext *ptr);
 void akerr_default_logger(const char *f, ...);
+/* defined in src/errno.c which is built dynamically at build time from system errno definitions */
+void akerr_init_errno(void);
 
 #define LOG_ERROR_WITH_MESSAGE(__err_context, __err_message)		\
     akerr_log_method("%s%s:%s:%d: %s %d (%s): %s", (char *)&__err_context->stacktracebuf, (char *)__FILE__, (char *)__func__, __LINE__, __err_message, __err_context->status, akerr_name_for_status(__err_context->status, NULL), __err_context->message); \
@@ -154,7 +160,7 @@ void akerr_default_logger(const char *f, ...);
     snprintf((char *)__err_context->function, AKERR_MAX_ERROR_FUNCTION_LENGTH, __func__); \
     __err_context->lineno = __LINE__;					\
     snprintf((char *)__err_context->message, AKERR_MAX_ERROR_CONTEXT_STRING_LENGTH, __message, ## __VA_ARGS__); \
-    __err_context->stacktracebufptr += snprintf(__err_context->stacktracebufptr, AKERR_MAX_ERROR_STACKTRACE_BUF_LENGTH, "%s:%s:%d: %d (%s) : %s\n", (char *)__err_context->fname, (char *)__err_context->function, __err_context->lineno, __err_context->status, akerr_name_for_status(__err_context->status, NULL), __err_context->message);
+    __err_context->stacktracebufptr += snprintf(__err_context->stacktracebufptr, AKERR_MAX_ERROR_STACKTRACE_BUF_LENGTH, "%s:%s:%d: %d (%s) : %s\n", (char *)__err_context->fname, (char *)__err_context->function, __err_context->lineno, __err_context->status, akerr_name_for_status(__err_context->status, NULL), (__err_context->message == NULL ? "" : __err_context->message));
 
 
 #define SUCCEED(__err_context)			\

scripts/generrno.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+srcdir=$1
+rm -f ${srcdir}/src/errno.c
+echo "#include <akerror.h>" >> ${srcdir}/src/errno.c
+echo "#include <errno.h>" >> ${srcdir}/src/errno.c
+echo "void akerr_init_errno(void) {" >> ${srcdir}/src/errno.c
+maxval=$(errno --list | cut -d ' ' -f 2 | sort -g | tail -n 1)
+errno --list | while read LINE; do
+    define=$(echo "$LINE" | cut -d ' ' -f 1);
+    value=$(echo "$LINE" | cut -d ' ' -f 2);
+    desc=$(echo "$LINE" | cut -d ' ' -f 3-);
+    echo "	akerr_name_for_status(${define}, \"${desc}\");" >> ${srcdir}/src/errno.c ;
+done;
+echo "}" >> ${srcdir}/src/errno.c
+sed "s/#define AKERR_LAST_ERRNO_VALUE .*/#define AKERR_LAST_ERRNO_VALUE      ${maxval}/" ${srcdir}/include/akerror.tmpl.h > ${srcdir}/include/akerror.h