无法编译Fortran模块:未定义的符号_main [英] Can't compile Fortran modules: Undefined symbol _main

问题描述

我最近一直在尝试在Fotran中使用库，但是我一直不断收到此错误消息

I've been trying lately to use libraries in Fotran, but I kept on getting this error message

体系结构x86_64的未定义符号: "_main"，引用自: 主可执行文件的隐式输入/启动 ld:找不到架构x86_64的符号 collect2:错误:ld返回1退出状态

Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status

我找不到针对它的任何特定解决方案.在这种情况下，我正在使用我为测试目的编写的简单模块来构建自己的一些库(此问题发生在静态库和共享库中).

which I cound't find any specific solution to it. In this case, I was working with some libraries that I built myself (this problem happened with static and shared libraries) from simples modules I wrote for purposses of tests.

当时我决定只尝试使用模块，并且不断收到与所使用模块相同的错误消息.我想知道是否有人可以帮助我判断我是否使用了错误的语法.这是模块

I decided to try only the modules then, and I kept getting the same error message regardes of the module I used. I would like to know if someone can help me on telling if I am using incorrect syntax. Here is the module

module modulo1

IMPLICIT NONE

real, parameter:: pi=3.1415

end module modulo1

这是主要的

program teste

use modulo1

IMPLICIT NONE

real :: r = 2

write (*,*) 'Área: ', pi*r**2

end program teste

这些是我用来编译的命令

These were the commands I used for compiling

gfortran -c modulo1.f90
gfortran -c teste.f90
gfortran -o teste.o modulo1.o

推荐答案

您的编译已损坏.命令

gfortran -o teste.o modulo1.o

告诉gfortran从名为modulo1.o的目标文件中创建名为teste.o的可执行文件.由于该模块文件不包含program，因此编译器无法找到其尝试构建的可执行文件的入口点. -o选项的参数是要生成的可执行文件的名称.

tells gfortran to create an executable called teste.o from the object file called modulo1.o. Since that module file doesn't contain a program the compiler can't find an entry point for the executable it is trying to build. The argument to the -o option is the name of the executable to build.

您可能应该用类似的内容代替该声明

You probably ought to replace that statement with something like

gfortran -o test teste.o modulo1.o

这将生成一个名为test的可执行文件.

which will build an executable called test.

从长远来看，学习如何使用make或其他构建系统.

In the longer run learn how to use make or another build system.

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