Compiler Option: -entry
Override the public exported name of the implicit user main function
Syntax
`
-entry < name >
`
Parameters
`name`
The custom name that overrides the public exported name of the implicit user main function
Description
The `-entry` compiler option changes the name of the publicly export symbol of the implicit user main function (automatically generated by fbc as start-up code).
It affects the start-up code and implicit user main, which is also affected by the module being the main module or not.
By default, fbc defines a publicly exported 'main' symbol in the main module as required by the run time start-up system code.
There is no other way currently to override fbc's use of the 'main' symbol other than to always compile and link separately.
Proceedings:
- The custom main function name must only be declared with the following signature (same parameter types, same return type, same calling convention) to be compatible with the (basic) main function:
`
'' internally the implicit main function is now named "custom_main"
Declare Function custom_main cdecl Alias "custom_main" ( ByVal argc As Long, ByVal argv As ZString Ptr Ptr ) As Long
`
- The (basic) main function must also be provided to satisfy the linker and start-up code. This might be defined in another libray or framework, in C, or ASM, or fb language as shown by the following minimum code example:
`
Function main cdecl Alias "main" ( ByVal argc As Long, ByVal argv As ZString Ptr Ptr ) As Long
'' .....
'' call the custom main
Return custom_main( argc, argv )
End Function
`
- Then compile with the `-entry custom_main` option.
Note:
This feature is being developed and may change in future (see `Compiler Option: -entry` in Documentation forum).
There will maybe a better way to deal with this: a compiler option that lets to outright specify an explicit "main".
Example
Example of program (`option_entry.bas`) trying to show the minimal code for fb language only:
`
'' option_entry.bas:
'' - demonstrate alternate named main function
'' as an alternate entry point for the implicit user main
'' - we also can compile and link in separate steps
'' compile: $ fbc -c -m option_entry option_entry.bas -entry custom_main
'' compile: $ fbc option_entry.o
'' OR
'' compile: $ fbc option_entry.bas -entry custom_main
'' internally the implicit main function is now named "custom_main"
Declare Function custom_main cdecl Alias "custom_main" ( ByVal argc As Long, ByVal argv As ZString Ptr Ptr ) As Long
'' But we still need a main() function to satisfy the linker and start-up code
'' - this might be defined in another libray or framework
'' - it's not so let's define it here for the demonstration
Function main cdecl Alias "main" ( ByVal argc As Long, ByVal argv As ZString Ptr Ptr ) As Long
'' just call our custom main for demonstration
Return custom_main( argc, argv )
End Function
'' ---------------------------------
'' START OF USER'S IMPLICIT MAIN
'' internally this is named "custom_main" and will automatically be
'' called by our custom frame work
Print "hello"
Sleep
'' END OF USER'S IMPLICIT MAIN
'' ---------------------------------
`
Version

- Since fbc 1.09.0

See also

- Compiler Option: -m
- Executables