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Hello World: Init and Version Check

A first and easy test that AML is set up properly and can be linked with a user program is to try to check that the headers and the library version match. All AML programs must also start by initializing the library and must end with a call to the cleanup function.

APIs

Setup/Teardown API

aml_init

aml_finalize

Version API

AML defines its version using semantic versioning, with a macro and variable for each subcomponent of the version number:

  • Version major: denotes ABI changes which prevent compatibility with previous major version ABI.
  • Version minor: denotes new features or improvement without breaking the old ABI.
  • Patch version: patch and fix releases only.

The full version string is also available directly.

/* see aml/utils/version.h for details */
#define AML_VERSION_MAJOR  ...
#define AML_VERSION_MINOR  ...
#define AML_VERSION_PATCH  ...
#define AML_VERSION_STRING ...

extern const int aml_version_major    = ...;
extern const int aml_version_minor    = ...;
extern const int aml_version_patch    = ...;
extern const char *aml_version_string = ...;

Usage

Both the setup and the version APIs are available directly from the main AML header.

#include <aml.h>

Initialization is done by passing pointers to the command-line arguments of the program to the library.

int main(int argc, char **argv){
...
if(aml_init(&argc, &argv) != 0){
  fprintf(stderr, "AML library init failure!\n");
  return 1;
}

Checking that the program is linked against the same version as the one used during compilation is as easy as comparing the header version AML_VERSION_MAJOR and the library-embedded version aml_version_major.

if(aml_version_major != AML_VERSION_MAJOR){
    fprintf(stderr, "AML ABI mismatch!\n");
    return 1;
}

Exercise

Write a "hello world" code that checks both major and minor versions of the code.

Click Here to Show/Hide Code

0_hello.c

You can find this solution in doc/tutorials/hello_world/.