BL51: Warning L1 (Unresolved External) Using Inline Assembly

Information in this article applies to:

• C51 Version 5.50a and later

QUESTION

I have a program that consists on several assembler files and a single C file that I compile with the #pragma SRC directive.

I'm receiving the following linker error messages:

WARNING L1:  UNRESOLVED EXTERNAL SYMBOL
SYMBOL:  ?C?STRCPY
MODULE:  ASDF.OBJ (ASDF)

WARNING L2:  REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL:  ?C?STRCPY
MODULE:  ASDF.OBJ (ASDF)
ADDRESS: 0223H

What am I doing wrong?

ANSWER

The linker is not finding the ?C?STRCPY segment. This has to do with the way you are creating the object files for your project.

When you compile a C file, the C compiler includes external references to the standard C library files in the OBJ file that is generated. When you use the #pragma SRC directive with a C file to generate an assembler SRC file, that information is no longer generated by the C compiler. So, you must generate it automatically (if there isn't another C file in your project that isn't compiled with the SRC directive.)

To successfully link your project, you must manually include the proper library file in your project.

• C51S.LIB: Small model library without floating-point math.
• C51C.LIB: Compact model library without floating-point math.
• C51L.LIB: Large model library without floating-point math.
• C51FPS.LIB: Small model library with floating-point math.
• C51FPC.LIB: Compact model library with floating-point math.
• C51FPL.LIB: Large model library with floating-point math.

MORE INFORMATION

• Refer to Warning L1 in the BL51 User's Guide.
• Refer to Warning L2 in the BL51 User's Guide.

SEE ALSO

• BL51: Unresolved Symbol ?C_STARTUP
• BL51: Unresolved External Symbol for Math and FP Routines
• BL51: Not Finding Some Functions in Libraries
• µVision1: Adding Library Files to a Project
• µVision: Specifying User Library Directories

Last Reviewed: Thursday, February 25, 2021