Q: What is the longest command line I can pass to gcc when it is
invoked by Make?
A: The arguments are passed to DOS Exec call (Int 21h function 4Bh)
via the transfer buffer which is 16KB-long. Apart of the command line, it
is also used to pass other info, such as the !proxy parameters and
the copy of the environment for the child program (let's say, less than
2000 bytes in most cases, but your mileage may vary). This leaves at
least 13K bytes for arguments (including a separating blank between any
two arguments). So unless your arguments span more than 160 screen lines,
you shouldn't worry. However, if your environment is very large
(some people need as much as 6KB to accommodate for all the variables
used by the various packages installed on their machine), be sure to
stub-edit the programs that spawn other programs to a larger transfer
buffer, or else they could fail.
The above limit depends on the size of the transfer buffer, so check the
size of the value recorded in the stub header of the parent program
before you pass extremely long command lines to its children. GCC is
the first program you should worry about, because the linker
(ld.exe) usually gets long command lines from GCC (they include
the list of all the object files and libraries to be linked).