CMake文档（例如当前version 3.11.2）状态
使用简单的标记语言显示CMake警告和错误消息文本。非缩进文本的格式为换行符分隔的换行段落。缩进文本被认为是预先格式化的。
但是，它没有提到任何标记格式。除非＆＃34;非缩进＆＃34; vs.＆＃34;缩进＆＃34;就是＆＃34;简单标记＆＃34;。
无论如何，我无法使用FATAL_ERROR模式。
此外，我注意到STATUS模式消息打印有前导--（两个破折号和空格）。当FATAL_ERROR消息中的每个换行符变成两行时，（恕我直言）看起来很糟糕。
现在我有一条多行消息，其中列出CMAKE_BUILD_TYPE中的错误以及接受的值。由于上述问题，我最终将消息打印为STATUS并将后续行缩进三个空格（因此它们与--很好地对齐）。然后我做一个简单的FATAL_ERROR只重复＆＃34;标题行＆＃34; （说明CMAKE_BUILD_TYPE是错误的）。这在控制台输出和cmake-gui上都可以接受。 （虽然cmake-gui上没有3个空格缩进......）
但是，我很惊讶这个主题的描述有多糟糕。而且似乎很长时间以来 - 例如问题[CMake] Extra blank lines with SEND_ERROR and FATAL_ERROR ?!现在已经有近9年没有得到答复......
是否有处理此类讯息的良好做法，建议或提示？或者首先应该避免它们？
答案 0 :(得分：4)
您是对的。 “简单标记”可以是非缩进（未格式化）或缩进（格式化）的。另外，非缩进文本在段落中用换行符分隔。这就是为什么最后在段落之间使用空白行。
以下是对各种消息的不断解释。警告类型和错误类型在格式化和未格式化文本方面表现相同。当然，区别在于CMake的处理和生成阶段会发生什么。为了提高可读性，您可以将字符串分成多个双引号，并将其串联起来。
# STATUS
message(STATUS
"This is a status message. It is prefixed with \"-- \". It goes to stdout. The "
"lines will wrap according to the width of your terminal.\n"
"New lines will begin a new line at column 1, but without the \"-- \" prefix, "
"unless you provide it; they will not create a blank line (i.e., new "
"paragraph). Spacing between sentences is unaltered by CMake.\n"
"-- Here's a new paragraph with an explicit \"-- \" prefix added.")
# no mode given (informational)
message(
"This is an informational message. It goes to stderr. Each line begins at column "
"1. The lines will wrap according to the width of your terminal.\n"
"New lines will begin a new line at column 1; they will not create a blank line "
"(i.e., new paragraph). Spacing between sentences is unaltered by CMake (3 spaces "
"preceded this sentence.).")
# WARNING--unformatted
message(WARNING
"This is an unformatted warning message. It goes to stderr. Each line begins "
"at column 3. The lines will wrap at a particular column (it appears to be "
"column 77, set within CMake) and wrap back to column 3.\n"
"New lines will begin a new paragraph, so they will create a blank line. A final "
"thing about unformatted messages: They will separate sentences with 2 spaces, "
"even if your string had something different.")
# WARNING--formatted and unformatted
message(WARNING
" This is a formatted warning message. It goes to stderr. Formatted lines will"
" be indented an additional 2 spaces beyond what was provided in the output"
" string. The lines will wrap according to the width of your terminal.\n"
" Indented new lines will begin a new line. They will not create a blank line."
" If you separate sentences with 1 space, that's what you'll get. If you"
" separate them with 2 spaces, that's also what you'll get.\n"
" If you want to control the width of the formatted paragraphs\n"
" (a good practice), just keep track of the width of each line and place\n"
" a \"\\n\" at the end of each line.\n \n"
" And, if you want a blank line between paragraphs, just place \"\\n \\n\"\n"
" (i.e., 2 newlines separated by a space) at the end of the first paragraph.\n"
"Non-indented new lines, however, will be treated like unformatted warning "
"messages, described above. They will begin at and wrap to column 3. They begin "
"a new paragraph, so they will create a blank line. There will be 2 spaces "
"between sentences, regardless of how many you placed after the period (In the "
"script, there were 4 spaces before this sentence).\n"
"And, as you'd expect, a second unindented paragraph will be preceded by a "
"blank line. But why would you mix formatted and unformatted text?")
我将其保存到Message.cmake中，并使用cmake -P Message.cmake 2> output.txt对其进行了调用。结果为以下标准输出：
-- This is a status message. It is prefixed with "-- ". It goes to stdout. The lines will wrap according to the width of your terminal.
New lines will begin a new line at column 1, but without the "-- " prefix, unless you provide it; they will not create a blank line (i.e., new paragraph). Spacing between sentences is unaltered by CMake.
-- Here's a new paragraph with an explicit "-- " prefix added.
output.txt文件包含：
This is an informational message. It goes to stderr. Each line begins at column 1. The lines will wrap according to the width of your terminal.
New lines will begin a new line at column 1; they will not create a blank line (i.e., new paragraph). Spacing between sentences is unaltered by CMake (3 spaces preceded this sentence.).
CMake Warning at MessageScript.cmake:19 (message):
This is an unformatted warning message. It goes to stderr. Each line
begins at column 3. The lines will wrap at a particular column (it appears
to be column 77, set within CMake) and wrap back to column 3.
New lines will begin a new paragraph, so they will create a blank line. A
final thing about unformatted messages: They will separate sentences with 2
spaces, even if your string had something different.
CMake Warning at MessageScript.cmake:28 (message):
This is a formatted warning message. It goes to stderr. Formatted lines will be indented an additional 2 spaces beyond what was provided in the output string. The lines will wrap according to the width of your terminal.
Indented new lines will begin a new line. They will not create a blank line. If you separate sentences with 1 space, that's what you'll get. If you separate them with 2 spaces, that's also what you'll get.
If you want to control the width of the formatted paragraphs
(a good practice), just keep track of the width of each line and place
a "\n" at the end of each line.
And, if you want a blank line between paragraphs, just place "\n \n"
(i.e., 2 newlines separated by a space) at the end of the first paragraph.
Non-indented new lines, however, will be treated like unformatted warning
messages, described above. They will begin at and wrap to column 3. They
begin a new paragraph, so they will create a blank line. There will be 2
spaces between sentences, regardless of how many you placed after the
period (In the script, there were 4 spaces before this sentence).
And, as you'd expect, a second unindented paragraph will be preceded by a
blank line. But why would you mix formatted and unformatted text?
摘要
信息消息（未提供模式）
状态消息
格式错误的警告和错误消息（字符串缩进）
格式化的警告和错误消息（缩进的字符串）