In latex when I force a newline in a caption with \\ it gives an error saying \Hy@tempa has an extra } runaway argument?
In latex when I force a newline in a caption with \\ it gives an error saying \Hy@tempa has an extra } runaway argument?
This error often happens when you force a newline with "\\" inside a caption because the caption text is going into places (like PDF bookmarks via hyperref) that don’t expect such commands. In other words, using "\\" directly in the argument of \caption makes it “fragile” and can confuse packages like hyperref. There are several ways to fix or work around this: 1. Use a protected newline command: If you really need the forced line break, you can try protecting it. For example: \caption{This is the first line\protect\\ and this is the second line.} This tells LaTeX not to expand "\\" too early. 2. Provide a “short” caption: Since the caption’s argument is used for things like the list of figures and PDF bookmarks (by hyperref), you can supply an optional short caption that omits the forced newline. For example: \caption[This is the caption without a newline]{This is the first line\\ and this is the second line.} Now, hyperref will use the short version (without "\\"), avoiding the error. 3. Use the caption package: The caption package offers more robust tools for handling multi‐line captions. Loading it (typically with \usepackage{caption}) may let you use line breaks more gracefully. In some cases, you can also use \newline instead of "\\": \caption{This is the first line\newline and this is the second line.} However, if you’re using hyperref, the optional short caption solution (as in step 2) is usually a good idea. In summary, the error is not really because you’re “illegal” using "\\" in a caption, but because the command ends up in a context (like PDF bookmarks) that doesn’t allow it. Either protecting it or supplying a simpler version for the bookmarks (via the optional short caption) should resolve the issue.
Testing if the previous output contains the string \protect: True
In latex when I force a newline in a caption with \\ it gives an error saying \Hy@tempa has an extra } runaway argument?
In latex when I force a newline in a caption with \\ it gives an error saying \Hy@tempa has an extra } runaway argument?
This error usually occurs because the caption text is a “moving argument” (i.e. used both in the float itself and in the list of figures/tables), and the plain \\ isn’t a robust command in that context. (Hyperref, for instance, processes the caption and ends up choking on the unprotected \\.) There are several ways to fix this: 1. Use \protect before \\ in your caption. For example: \caption{This is the first line\protect\\ and this is the second line.} 2. Alternatively, if you don’t need the forced line break in the list of figures (or tables), you can supply an optional short caption without the line break. For example: \caption[This is the first line and this is the second line]{This is the first line\protect\\ and this is the second line.} 3. You may also try using \newline instead of \\: \caption{This is the first line\newline and this is the second line.} (In many cases \newline is robust enough to work in captions.) Either of these solutions should resolve the “\Hy@tempa has an extra } runaway argument” error.
Testing if the previous output contains the string \protect: True